Log some handled exceptions

Summary:
When events are fired in our application, some exceptions
are silently handled and reported as error in the actions
report.

This makes difficult to track these exceptions, as they
are logged in the requester app or silently discarded.

We so explicitely log them.

Reviewers: dereckson

Subscribers: alken-orin

Differential Revision: https://devcentral.nasqueron.org/D338